In the case of existing circuits, no corners have been cut in ensuring safety is paramount.

The owners of Germany's Nurburgring, itself barely 25 years old and originally built with the highest safety standards in mind, have invested about $74m in improving the safety of the drivers and the spectators in recent years.

Nowadays, it is customary for new circuits where money is no object, such as the $150m Sakhir circuit in Bahrain, to be designed as much with driver safety in mind as spectator enjoyment.

Indeed, in 2007 Sakhir became the first F1 track to earn the FIA Institute Centrex of Excellence award, given for excellent safety, race marshal and medical facilities.

Investment in trackside facilities is vital. Two ambulances and a helicopter manned by a doctor, two paramedics and a pilot stand by throughout the race.

A second helicopter is kept ready outside the circuit and four additional ambulances -- ready to ferry the injured to any one of 15 hospitals on alert during a race weekend -- are posted along the circuit.

As circuits have upped their game at huge cost, so a lucrative industry has grown to keep drivers safe in other ways.

Drivers in an F1-standard Nomex overall can survive for 35 seconds in temperatures of 840 degrees Celsius -- hotter than an apartment fire.

It has been mandatory since 2003 for drivers to wear the HANS (Head And Neck Support) device, which protects the head from trauma by restricting its movement in a crash.

They are worn over the shoulder and attached to helmets, themselves almost unrecognizable from their 70s counterparts.

A modern flame-proof helmet is layered with a number of different materials, including carbon fiber and a substance used in some bulletproof vests.

Technological developments in the field of safety have helped shape not just the way cars look -- such as higher cockpit sides -- but also how they behave in an accident.

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Crashes a driver escapes relatively unharmed from today -- Robert Kubica's 175mph horror smash in Canada in 2007 springs to mind -- could have killed him not so long ago.

Kubica had the benefit of the survival cell monocoque in his BMW Sauber, a closed structure containing the cockpit and fuel tank and constructed of carbon fiber, Kevlar, honeycomb structures and metal.

Pre-season structural tests on each chassis, first introduced in 1985, are extremely demanding.

An F1 car's incredible strength -- and, partly, cost -- is down to its carbon fiber construction, which is four times lighter and seven times stronger than its F1 predecessor, aluminum.

However, the labor-intensive production process means it can cost $220,000 for around 50 kilos of monocoque, including design and development.

Tethers are designed to prevent wheels from flying off, formerly a common sight and what may have killed Senna. A flying wheel killed a marshal at Melbourne's Albert Park in 2001, leading to the raising of its safety fences' height to 3.80 meters (12ft).

Many of these advances have been driven by the Expert Advisory Safety Committee, established in the wake of Senna's demise.

It was the forerunner to Institute for Motor Sport Safety, founded and funded by motorsport's governing body, the FIA, via its UK-based Foundation charity.

The FIA Foundation was set up in 2001 following the $300m sale of the 100-year commercial rights to F1. The FIA itself makes a minimum of $25m a year from F1, excluding often substantial fines.

Around $60m of the $100m fine imposed on McLaren for their part in last year's spy scandal went to the FIA, who set up the Motor Sport Safety Development Fund.

"Formula One since 1995 has been an outstanding example of what is possible, given virtually unlimited funding and the application of hard science," said Michael Henderson, chairman of the Australian Institute for Motor Sport Safety.

The Grand Prix Drivers' Association (GPDA) pressure group also ensures that money continues to be ploughed into safety.

However, no driver did more for safety improvements than three-time champion Jackie Stewart, who raced in an era when drivers were killed with frightening regularity.

In the 60s and 70s, for every 10 accidents there was either a death or a serious injury. Now the ratio is around one in 300.

But despite no driver dying since Senna, Stewart believes that F1 can never get complacent.

"The moment somebody dies there is a new awakening," he forewarned.

"So far we have been incredibly lucky. You can't go on without something going wrong somewhere. We are on the slate to have a big shunt."